Functional Characteristics of Fungal Communities in the Rhizosphere of the Endangered Plant Abies ziyuanensis

First discovered in 1977, <i>Abies ziyuanensis</i> (Pinaceae) is listed as an endangered species by the International Union for Conservation of Nature (IUCN); its population continues to decline. Analyzing the rhizospheric fungal communities in the two largest populations of <i>A. ziyuanensis</i> within the Yinzhu Laoshan National Nature Reserve in Guangxi Zhuang Autonomous Region, China, and factors influencing the rhizosphere will establish a theoretical framework for the reintroduction of <i>A. ziyuanensis</i>. This study used ITS rRNA gene high-throughput sequencing and statistical data analysis to compare the functional diversity and structure of the molecular ecological network of rhizospheric fungal communities between <i>A. ziyuanensis</i> populations in Yinzhu Laoshan mountain in Guangxi at two sites, Shenbaotang and Sanjiaohutang. A total of 1755 OTUs were identified from the rhizospheric samples of 30 <i>A. ziyuanensis</i>; these were classified into seven trophic modes and 81 functional guilds. The most important functional types corresponded to the fungal phyla Ascomycota, Mortierellomycota, and Basidiomycota. Changes in the structure of the functional molecular ecological network of the rhizospheric fungal communities of <i>A. ziyuanensis</i> were mainly related to soil nutrient conditions and soil water content, with AK and TK being the most critical. The functional molecular ecological networks of the rhizosphere of <i>A. ziyuanensis</i> differed among populations; distinct functional-gene profiles were detected in the rhizosphere microbiomes of different <i>A. ziyuanensis</i> populations. These findings provide insight into the role of unique rhizospheric fungi in the growth and environmental adaptation of <i>A. ziyuanensis</i>, and for the discovery of superior rhizosphere-promoting fungi.